Bumper jack



April 1955 c. E. BRANICK 2,740,607

BUMPER JACK Filed Dec. 11, 1953 Q 3 Q /5 /f IN V EN TOR. mrZgJ ZYB/mzzk Uite My invention relates to fiuid pressure operated lifting jacks and more particularly to bumper jacks for lifting automotive vehicles and the like.

This application is a continuation-in-part of my copending application filed July 10, 1952, entitled Bumper Jack, now United States Patent No. 2,669,422 issued February 16, 1954.

The primary object of my invention is the improvement of the connecting means between the plunger rod crosshead and load engagaing means of a bumper jack of the type disclosed in my above identified U. S. patent so that such bumper jack may be capable of lifting great loads without bringing about undue frictional engagement or binding between the several moving parts thereof.

A still further object of my invention is the provision of a bumper jack of the class described, which may be operated with a minimum of power and with a maximum of efiiciency, which has a relatively small number of working parts and which is rugged and durable in construction.

The above and still further objects of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.

Referring to the drawings wherein like characters indicate like parts throughout the several views:

Fig. l is a perspective view of my novel structure as seen from the front thereof;

Fig. 2 is an enlarged view in side elevation of the structure of Fig. 1, but showing a different position of some of the parts thereof; and

Fig. 3 is a view partly in vertical section and partly in top plan, as seen from the line 33 of Fig. 2.

Referring with greater particularity to the drawings, the number 1 indicates a mounting base having secured to its central portion a vertically disposed cylinder 2, upwardly and rearwardly from the upper portion of which the handle 3 projects. A pair of wheels 4 are journalled to an axle 5 extending through ears 6 on flanges 7 pro jecting upwardly from opposite sides of, and forming part of frame 1. As shown, the wheels 4 are engageable with the ground X only when the forward end 8 of the frame 1 is elevated by pressing downwardly and backwardly upon the handle 3.

A pair of opposed channel irons 9 are secured to diametrically opposite side portions of the cylinder 2 and extend longitudinally thereof for substantially the length of the cylinder 2. Opposite outer side portions of the channel members 9 define front and rear parallel guide rails 10 and 11 respectively on opposite sides of said cylinder 2. A piston 12, see particularly Fig. 3, is mounted for reciprocal movements within the cylinder 2 and has a plunger rod 13 projecting upwardly through a head 14 on the cylinder 2. The cross-head 15 is secured to the upper end of the plunger rod 13 and projects laterally outwardly therefrom in opposite directions, overlying the upper ends of the rail forming members 9. Rigidly secured to the opposite ends of the cross-head 1S and depending vertically therefrom, adjacent the States Patent 0 2,740,607 Patented Apr. 3, 1956 rail forming members 9, are a pair of lifting links 16. Lifting links 16 have pivotal connections at their lower ends with carriage structure 17, as indicated at 18. It will be noted that pivotal connections 18 are intermediate the front and rear guide rails 10 and 11 and vertically above the stub axles 22 and 21.

Carriage structure 17 includes side frame members 18 and guide rail engaging roller elements 19 and 20 carried thereby. Roller elements 19 are journalled on inwardly projecting stub axles 21 and are engageable one each with one of the front guide rails 10. Roller elements 20 are upwardly spaced and laterally offset from the roller elements 19, and are journalled on stub axles 22, projecting inwardly from said side frame members 18'. It will be noted that roller elements engage and ride upon the rear guide rails 11. The forward end portions of the side frame members 18 are tied together by a cross sectionally rectangular horizontally disposed tubular lifting beam 23 in which are adjustably slidably mounted, in side by side relationship, a pair of beam sections 24. Lifting beam sections 24 at their extreme outer ends are preferably provided with yoke-like load receiving heads 25 When the above structure is wheeled or otherwise placed in operative position, wherein the yoke-like heads 25 underlie the bumper, or other horizontally disposed bar-like portion of an automotive vehicle, air is introduced into the cylinder 2 by means of an air hose, not shown, being applied to the valve equipped upper end portion 26 of an air inlet pipe 27. Air from the tube 27 enters the bottom of the cylinder 2 below the piston and causes elevation of the plunger rod 13 and parts carried thereby. Under such an arrangement, irrespective of the load carried by the yoke-like heads 25, the weight will be equally distributed against the front and rear guide rails 10 and 11 through the medium of the roller elements 19 and 20 respectively. Furthermore no binding action or undue friction is brought to bear between the plunger rod 13 and the cylinder head 14 in view of the fact that the lifting links 16 are always in a vertical position parallel to the guide rails 10 and 11 and plunger rod 13. Air is discharged from the lower end of the cylinder whereby to cause lowering movements of the plunger rod 13 and parts carried thereby, through the medium of an outlet valve, not shown.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the above objects, and while I have disclosed a commercial embodiment thereof, it should be obvious that same is capable of modification without departure from the scope of the appended claims.

What I claim is:

1. In a portable fluid pressure operated jack, a mounting base, a vertically disposed pressure cylinder secured to said base, a piston within said cylinder, a plunger rod secured to said piston and projecting upwardly through the upper end of said cylinder, a cross-head mounted on the outer projecting portion of said plunger rod and extending laterally outwardly therefrom in opposite directions, front and rear vertical parallel guide rails at opposite sides of said cylinder, a pair of lifting links connected one each to opposite ends of said cross-head and depending vertically therefrom adjacent said guide rails, carriage structure including side frame members pivotally connected one each to lower end portions of said lifting links at points intermediate the front and rear guide rails, vertically spaced front and rear guide rail engaging antifriction means connected to and carried by each of said side frame members, and transverse load engaging means connecting said side frame members forwardly of said pivotal connections and said anti-friction means, whereby a load supported by said load engaging means is equally distributed against-the front and rear guide rails through I said front and rear guide rail engaging anti-friction means.

2. The structure defined in claim 1 in which said front and rear guide rails are in the nature of opposed longitudinally extended U-shaped channel members secured to the opposite sides of said cylinder.

3. The structure defined in claim l wherein said pivotal connections of the side frame members to the lower end portions of the lifting links is vertically above the connection of the antifriction means to each of said side frame members; 7 r 7 References Cited in' the file of this patent UNITED STATES PATENTS 

